We have completed the first phase of this study examining responses to acute administration of triazolam at different phases of the menstrual cycle. We now propose to extend this research to a stimulant drug, d- amphetamine. This second phase will investigate interactions between circulating ovarian hormones (progesterone and estrogen) and subjective and behavioral responses to d-amphetamine in normal healthy women. We will administer amphetamine and a placebo in the luteal and follicular phases of the menstrual cycle, and assess measures of mood, physiological responses and psychomotor performance. CRC resources are needed to determine plasma levels of hormones, from a single sample on each session. The effects of ovarian hormones on responses to psychoactive drugs have both clinical and basic science implications.